Knowledge of the present-day crustal in-situ stress field is a key for the understanding of geodynamic processes such as global plate tectonics and earthquakes. It is also essential for the management of geo-reservoirs and underground storage sites for energy and waste. Since 1986, the World Stress Map (WSM) project has systematically compiled the orientation of maximum horizontal stress (). For the 30th anniversary of the project, the WSM database has been updated significantly with 42,870 data records, which is double the amount of data in comparison to the database release in 2008. The update focuses on areas with previously sparse data coverage to resolve the stress pattern on different spatial scales. In this paper, we present details of the new WSM database release 2016 and an analysis of global and regional stress pattern. With the higher data density, we can now resolve stress pattern heterogeneities from plate-wide to local scales. In particular, we show two examples of 40°-60° rotations within 70 km. These rotations can be used as proxies to better understand the relative importance of plate boundary forces that control the long wave-length pattern in comparison to regional and local controls of the crustal stress state. In the new WSM project phase IV that started in 2017, we will continue to further refine the information on the orientation and the stress regime. However, we will also focus on the compilation of stress magnitude data as this information is essential for the calibration of geomechanical-numerical models. This enables us to derive a 3-D continuous description of the stress tensor from point-wise and incomplete stress tensor information provided with the WSM database. Such forward models are required for safety aspects of anthropogenic activities in the underground and for a better understanding of tectonic processes such as the earthquake cycle.

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The World Stress Map (WSM) is a global compilation of information on the present-day crustal in situ stress within the upper 40 km of the lithosphere. It is a collaborative project between academia and industry that aims to characterize the crustal stress pattern and to understand the causes of these stresses. The present-day stress information in the WSM database is derived from a variety of methods, primarily earthquake focal mechanism, borehole breakouts and drilling-induced tensile fractures (from borehole image or multi-arm caliper log data), in situ stress measurements (overcoring, hydraulic fracturing), and geologic indicators such as fault slip and volcanic vent alignment. The in situ stress information in the WSM database is compiled in a standardized format and quality-ranked for reliability and comparability on a global scale.

Early phases of the Australian Stress Map project revealed that plate boundary forces acting on the Indo-Australian Plate control the long wavelength of the maximum horizontal present-day stress orientation in the Australian continent. However, all numerical models of the stress field to date are unable to predict the observed orientation of maximum horizontal stress in the northeast of New South Wales, Australia. Recent coal seam gas exploration in the Clarence-Moreton Basin, eastern Australia, provides an opportunity to better evaluate the state of crustal stress in this part of the continent where only limited information was available prior to this study. Herein, we conduct the first analysis of the present-day tectonic stress in the Clarence-Moreton Basin, from drilling-induced tensile fractures and borehole breakouts interpreted using 11.3 km of acoustic image logs in 27 vertical wells. A total of 2822 drilling-induced stress indicators suggest a mean orientation of N069°E (AE23°) for the maximum horizontal present-day stress in the basin which is different from that predicted by published geomechanical-numerical models. In addition, we find significant localised perturbations of borehole breakouts, both spatially and with depth, that are consistent with stress variations near faults, fractures and lithological contrasts, indicating that local structures are an important source of stress in the basin. The observation that structures can have a major control on the stresses in the basin suggests that, while gravity and plate boundary forces have the major role in the long wavelength (first-order) stress pattern of the continent, local perturbations are significant and can lead to substantial changes in the orientation of the maximum horizontal present-day stress, particularly at the basin scale. These local perturbations of stress as a result of faults and fractures have important implications in borehole stability and permeability of coal seam gas reservoirs for safe and sustainable extraction of methane in this area.

Knowledge of the crustal stress state is important for the assessment of subsurface stability. In particular, stress magnitudes are essential for the calibration of geomechanical models that estimate a continuous description of the 3-D stress field from pointwise and incomplete stress data. Well established is the World Stress Map Project, a global and publicly available database for stress orientations, but for stress magnitude data only local data collections are available. Herein, we present the first comprehensive and open-access stress magnitude database for Germany and adjacent regions, consisting of 568 data records. In addition, we introduce a quality ranking scheme for stress magnitude data for the first time.

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Iceland is located on the Mid-Atlantic Ridge which is the plate boundary between the Eurasian and the North American plates. It is one of the few places on earth where an active spreading centre is located onshore but the stress pattern has not been extensively investigated so far. In this paper we present a comprehensive compilation of the orientation of maximum horizontal stress (S Hmax ). In particular we interpret borehole breakouts and drilling induced fractures from borehole image logs in 57 geothermal wells onshore Iceland. The borehole results are combined with other stress indicators including earthquake focal mechanism solutions, geological information and overcoring measurements resulting in a dataset with 495 data records for the S Hmax orientation. The reliability of each indicator is assessed according to the quality criteria of the World Stress Map project.The majority of S Hmax orientation data records in Iceland is derived from earthquake focal mechanism solutions (35%) and geological fault slip inversions (26%). 20% of the data are borehole related stress indicators. In addition minor shares of S Hmax orientations are compiled, amongst others, from focal mechanism inversions and the alignment of fissure eruptions. The results show that the S Hmax orientations derived from different depths and stress indicators are consistent with each other.The resulting pattern of the present-day stress in Iceland has four distinct subsets of S Hmax orientations. The S Hmax orientation is parallel to the rift axes in the vicinity of the active spreading regions. It changes from NE-SW in the South to approximately N-S in central Iceland and NNW-SSE in the North. In the Westfjords which is located far away from the ridge the regional S Hmax rotates and is parallel to the plate motion.